More than 20 years ago, when Gary Appel—a recently-retired private equity fund manager—and his wife, Sallie Krawcheck, a one-time Bank of America honcho who has been called "one of the most powerful women in American finance," were contemplating a Hamptons summer home, Mr. Appel was ready to walk away from a deal because of a $20,000 discrepancy between the couple's offer and the seller's demands. In light of the appreciation of Hamptons real estate that has occurred in the interim, it's a story that Ms. Krawcheck, who convinced her husband to think of the place as a long-term investment, reminds him about fondly, particularly from their front porch in Quogue.